Process for applying labels with delayed adhesive activation

ABSTRACT

The process for applying labels to articles by first adhering a limited portion of the label to the article and subsequently rendering additional portions of the label adhesive so that they will adhere to the article after the label is affixed to the article. The leading and trailing edges of the label may be bonded to the article or each other to affix the label to a container or other such article. The portions of the label between the leading and trailing edges may be either provided with an adhesive agent that is in a non-adhesive state or be formed from a label material which is not normally adhesive but can be rendered adhesive through an additional process step. For example, coated polyethylene film can be applied to a container by means of a hot melt adhesive and then subsequently heated to a temperature at which the polyethylene material becomes adhesive causing it to stick to the container. Other labeling materials can be printed with an adhesive that remains substantially non-adhesive until heated or activated by means of radiation, application of a chemical activating agent or by application of mechanical force.

This application claims the benefit of U.S. Provisional Application No.60/021,701, filed Jul. 12, 1996.

TECHNICAL FIELD

The present invention relates to labeling articles with labelingmaterial that can be rendered adhesive subsequent to its application tothe article.

BACKGROUND ART

Articles are labeled to identify the contents of containers and provideattractive point of sale product presentation. Labels are applied byroll-fed, sleeve, or cut and stack methods. Different labeling materialshave been developed including paper labels, film labels, laminated filmand paper labels, styrene foam, and laminated film and foam. Theappearance of labeled containers can be improved by shrinking plasticlabel material to fit tightly around the container and even follow thecontours of a container to provide an enlarged billboard appearance.

Generally, labels are either spot-adhered to articles or are applied aspressure sensitive labels. Pressure sensitive labels generally arecompletely coated with an adhesive material and are one of the mostexpensive labeling options. Labels are also applied to containers byadhesive applied immediately prior to labeling. The adhesive may beapplied in a variety of patterns including leading and trailing edge,spaced dots, picture frame, or overall adhesive.

In some applications, the minimum amount of adhesive is desired,particularly if a container is to be recycled. The prior art has failedto provide an inexpensive and effective labeling process that minimizesthe use of adhesives, solvents, or complex welding mechanisms.

Other applications are better suited to a fully adhered label for anarticle or container. Generally, the more adhesive that is applied to alabel, the greater the likelihood that the label will develop wrinklesor surface distortions. Distortions can also be caused by heat shrinkinglabel material over the top of adhesive spots.

One application where a completely adhesive surface is desirable iswhere a label is to be applied over a previously printed can. Such aprocess would make it possible to use cans that have an outmodeddecoration. By fully adhering a label to an overlabeled container,removal of the label can be substantially prevented or impeded.

Another situation where a fully adhesive label is desirable is in thelabeling of containers that undergo a pasteurization process. Forexample, in breweries, bottles are pasteurized after filling by placingthem in hot water or steam which can cause labels to peel off thecontainers or create bubbles and wrinkles under the label.

Another situation wherein fully adherent labels would provide anadvantage is in the use of thin stretchable labels. For example,inexpensive polyethylene or polypropylene labels can be produced thatoffer many excellent characteristics for labeling but are elastic andcan stretch. If a thin film label could be made to adhere directly tothe article or container, problems relating to label stretch afterapplication to the container could be eliminated.

One prior art approach to providing a fully adhesive label for cans wasproposed in Canadian Patent No. 1,012,906 to Germiat. The Germiat patentproposed using a coextruded label material wherein a extruded layer ofsurlyn was provided to act as an adhesive. Both the label material andcan to be labeled were heated in the Germiat method while the label wasbeing applied to cause the label to become adhesive and fully adhere tothe container. Disadvantages associated with the Germiat label were thatthe adhesive did not always activate uniformly which could lead towrinkles or bubbles forming between the container and label, especiallyafter pasteurization.

In another unique labeling application, heat is used to shrink labelsover the contours of containers as is disclosed in U.S. Pat. No.4,704,173 which issued to Hoffman. With shrink labeling, as proposed inthe Hoffman patent, the leading and trailing edges of the label have hotmelt adhesive applied thereto in a generally vertical line at theleading and trailing edges of the label. The balance of the label ispreferably free of adhesive so that the label can shift as it shrinkswithout causing wrinkling of the label material. While the wrap shrinklabeling process of the Hoffman patent is popular and effective for manylabeling applications, the lack of a full coating of adhesive makes thisapproach inappropriate for some applications.

The above problems and limitations relating to the prior art areaddressed by Applicant's invention as summarized below.

SUMMARY OF THE INVENTION

This invention provides a labeling method in which a label is placed ina desired position on an article and then subsequently affixed to thearticle through the activation of a potentially adhesive coating, layeror surface that is substantially not adhesive when the label isinitially placed on the article.

According to one approach to practicing the present invention, a labelis applied to the surface of the article by adhering a first portion ofthe label to the article and then wrapping the label around the article.A second portion of the label is adhered to either the article or thelabel. The label includes a potentially adhesive interface which isdefined as a surface which does not adhere to the article but can slideor shift while the label is wrapped around the article. The potentiallyadhesive interface can be later caused to adhere to the article bysubsequent processing steps.

According to this method, rapid roll-fed label application can beachieved with a rapid tack hot melt glue applied to the leading andtrailing edges of the label. The potentially adhesive interface can beapplied by co-extrusion with the label, printing an adhesive on thelabel, printing an ink on the label which can be made adhesive, orspraying a coating on the label. Alternatively, the potentially adhesivesurface could actually be the polymer used to form the label or thecontainer.

The potentially adhesive interface could also be a coating or surface ofthe article. A coating of the article could be later activated bysubsequent heating, application of radiant energy, exposure to achemical agent or by application of a mechanical force.

Another advantage of fully bonding a label to an article is that thelabel can function to support and reinforce glass bottles allowing forthinner bottle walls and less chance of container breakage. A fullyadherent label can also be provided that extends to the cap area of acontainer and can provide a very effective tamper evident labelingmechanism.

According to another aspect of the present invention, the labeling filmcan be caused to shrink about the contours of the container. In thecourse of the shrinking step, particularly when heat is used to causethe labeling film to shrink, a heat activatable adhesive can beactivated.

Other approaches to the invention may include the use of a solvent toform an adhesive in situ on the leading and trailing or other portionsof the label to render material adhesive in localized areas. Spotapplication of radiation or heat could also be used to provide, forexample, a leading and trailing edge adhesive portion of the label whileleaving the portions of the label between leading and trailing edgessubstantially unactivated until after the label has been placed on thecontainer.

While the above methods are directed to roll-fed and cut and stacklabeling techniques, the present invention can also be practiced withsleeve applied labels. Briefly, sleeve applied labels can be providedwith a potentially adhesive interface between the article to be labeledand the sleeve. The sleeve may then be positioned on the article andeither locally affixed to the article by fingers which hold the label inplace on the article by a localized application or activation ofadhesive, or by other mechanical retention mechanisms. The label canthen either be shrunk on to the article or adhered to the article byactivating the potentially adhesive interface after the step of affixingthe label on to the article.

According to the invention, a new label can be provided for containerswhen there is a need to change the labeling on the container due to aningredient change or a mistake in the printing of containers such ascans that are directly lithographed. It may also be advantageous to beable to provide a new label for an article if government labelingregulations change. The present invention can be used in conjunctionwith any article. However, one particularly appropriate field is thelabeling of containers of various types. Containers including plasticcontainers, glass containers, metal cans and paperboard containers areall widely used and can benefit from the advantages of the presentinvention.

These and other advantages and objects of the invention will becomereadily apparent upon review of the attached drawings in light of thedetailed description of the drawings and the preferred embodiments ofthe invention that follow.

BRIEF DESCIPTION OF THE DRAWING

FIG. 1 is a flow chart illustrating the steps of the labeling method ofthe present invention.

FIG. 2 is a schematic plan view of a roll fed labeling line.

FIG. 3 is a schematic perspective view of a sleeve applied labelingmethod.

FIG. 4 is a schematic perspective view of a cut and stack labelingmethod.

FIG. 5 is a plan view of a label having a leading and trailing edgeadhesive pattern and a coating of a potentially adhesive materialbetween leading and trailing edges.

FIG. 6 is a schematic view showing a container with a label beingapplied thereto with a leading and trailing edge glue pattern and anintermediate potentially adhesive interface.

FIG. 7 is a schematic view of a container which is being subjected tohot air for shrinking portions of the label around the contours of thecontainer.

FIG. 8 is a schematic view of a container to which hot air is directedto cause the potentially adhesive interface to be activated and fullyadhered to the container.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, a flow chart showing various alternatives andan example of an arrangement of the steps of the invention are showndiagrammatically. Each of the figures of the drawing are referred to inthe appropriate steps illustrated in FIG. 1.

Referring to FIGS. 1 through 4, the present invention is shown as beingamenable to a wide variety of labeling techniques. Specificallyillustrated are roll fed labeling, as shown in FIG. 2, sleeve appliedlabels, as shown in FIG. 3, and cut and stack labels, as shown in FIG.4. With any of the labeling methods shown in FIGS. 2 through 4, a labelis provided for labeling an article such as a container.

Referring now to FIG. 2, a roll fed labeler 10 is shown diagrammaticallywherein a roll 12 of label material is unwound with a web 14 of labelingmaterial being fed to a label cutter 16. A vacuum drum 18 receives andsupports individual labels 20 that are cut off by the cutter 16 from theweb 14. The vacuum drum 18 supports the labels 20 as glue is applied bya glue applicator 22 prior to applying the label 20 to a container 24.Containers 24 are fed to the vacuum drum 18 in a sequential relationshipby means of a star wheel 26 which picks up the containers 24 from aconveyor 28, feeds into the vacuum drum 18 and then deposits them afterlabeling on the conveyor 28.

A wide variety of labeling materials can be provided including paperlabels, paper/polypropylene laminate labels, expanded styrofoam labels,film labels including polyethylene, polypropylene, and polystyrene filmsin combinations or laminations of such materials.

The labels can be cut by the cutter 16 into lengths sufficient to fullyencircle a container 24 or provide only a spot label on the container24. The glue applicator 22 can apply leading and trailing edge gluepatterns, picture frame, spaced dots, lines of adhesive or a broad bandknurled roll adhesive pattern.

According to the present invention, the glue applicator 22 would notprovide a full pattern adhesive, but would leave substantial portions ofthe label 20 without application of any adhesive which is in an adhesivestate prior to application of the label 20 to the container 24. The glueapplicator 22 can be used to apply hot melt glue, cold glue or a solventwhich can form an adhesive in situ when applied to a label 20.Alternatively, the glue applicator 22 could be another apparatus capableof forming an adhesive portion on a label 20. For example, a hot bar,hot air jet, radiation emitter or a water applicator could be providedthat could be matched to a particular label or label coating to providea localized adhesive which would enable a container 24 to pick up thelabel 20 and tack the label 20 to the container 24 as it is wrapped bythe label 20.

Referring now to FIG. 3, the sleeve applied labeling method isillustrated by a bottle 30 disposed over a sleeve label 32 which ispositioned to be slipped on to the bottle 30 from below. The disclosureof a sleeve applied labeling system as disclosed in U.S. Pat. No.3,822,459 is hereby incorporated by reference.

Referring now to FIG. 4, a cut an d stack labeling magazine is shownwherein a label 36 is picked up by an object 38 from a label magazine34.

Regardless of the label supply mechanism, a potentially adhesiveinterface is provided between the label and the article to be labeled.The potentially adhesive interface can comprise a printed adhesivematerial on the label, a layer of latent adhesive material which isco-extruded with the polymer label, a separate sheet made up of adhesivematerial, a coating provided on the article to be labeled or a surfaceof the polymer label material or article which can be rendered adhesiveby a subsequent processing step.

As shown in FIG. 5, a label segment 20 is shown which could be providedby the roll fed labeler of FIG. 2 or cut and stack labeler of FIG. 4.The label 20 includes a leading edge adhesive strip 40 and a trailingedge adhesive strip 42. The portions of the label 20 not covered by theleading and trailing edge adhesive strips 40 and 42 are coated with alatent adhesive coating 44 which can be provided as described above.

As shown in FIG. 6, the leading edge adhesive 40 is presented to thecontainer 24 to provide a quick pick up as the container contacts thelabel segment 20. The container is rotated to cause the label to wraparound the container 24 until the trailing edge adhesive 42 overlaps andbonds to the outwardly facing portion of the label 20. As the label 20is wrapped around the container 24, the label is permitted to shift andmove freely without any interference from an active adhesive which couldcause the label to begin to bond and result in wrinkles or other surfaceimperfections. While the latent adhesive coating 44 could have someminimal adhesive properties, the preferred coating would not stick tothe container during the labeling process at least until the label isaffixed to the container. The label could be directly affixed to thearticle by means of the trailing edge adhesive 42.

Alternatively, the label could be affixed by partially shrinking asleeve 32 over the contours of a bottle 30 or other container such as ametal can. Fingers 46 hold the label 20, or sleeve 32, on the bottle 30,or other container, while the label is being subjected to hot air from ahot air source 48. After the label is located and affixed to the articleor container, the shrinking of the label over the contours can continueas shown in FIG. 7. Whether or not shrinking over the contours isrequired, the label can be permanently attached over its entire surfaceby activating the potentially adhesive interface as shown in FIG. 8,wherein hot air is directed from a hot air source 50 to form a fullyadhered label 52.

Various mechanisms can be utilized to provide the delayed adhesivefunction of the present invention. The selection of the potentiallyadhesive interface will determine the activation mechanism. An exampleof a heat activated adhesive would be to spray Century CX887 orCelluCraft White Coat adhesives sold by Century Adhesives and CelluCraftrespectively on the inner side of a polyethylene and polypropylenelaminate film label. Other alternative activation mechanisms couldinclude radiation which may take the form of a infrared or other lightsource, microwave radiation or other commercially available radiationsource which can activate an adhesive or polymer to cause it to becomeadhesive. Other types of latent adhesives could be activated byapplication of water, application of chemical of fluids or gases or atime delayed adhesive which would become more adhesive over time.Another latent adhesive could be a micro encapsulated adhesive whichcould include micro capsules of, for example, epoxy components whichwhen subjected to pressure or mechanical stresses would rupture andcause an epoxy bond to be formed between the article and the label.

While the invention, as described above, generally focuses onapplication of the potentially adhesive interface to the label, it isalso possible that the potentially adhesive interface could be formed onthe bottle or other article by spraying, dipping, or otherwise coatingthe article prior to labeling. If the potentially adhesive interface isformed on the container or article, it is maintained in a latentadhesive state prior to application of the label and only activatedafter the label is affixed in the desired orientation on the article orcontainer.

While the potentially adhesive interface is generally anticipated to bean interface that would cover the entire area between the label and thebottle, it is also anticipated that a partial coverage of the area couldbe used. For example, if it would be desirable to provide a coupon onthe label it would be preferable to avoid application of the latentadhesive material behind the coupon so that it can be readily separatedform the article or container.

Referring now to FIG. 1, the last step is the provision of a fullybonded label on an article or container. By bonding the label to thearticle after it has assumed its final position on the article orcontainer, it is believed that a consistent high quality label can beprovided.

The above description of preferred embodiments of the invention isprovided by way of example and not by way of limitation. The broad scopeof applicant's invention is to be construed in accordance with thefollowing claims.

What is claimed is:
 1. A method of labeling articles with labels toprovide a full coat bonding between the article and the labelcomprising:providing an atricle to be labeled; providing a label to beapplied to the article, said label comprising a fully coated labelhaving a potentially adhesive interface substantially covering one sideof the label; initially affixing a portion of the label to the articleby adhering the first portion of the label to the article; wrapping thelabel completely around the article with all of the potentially adhesiveinterface in contact with the article; adhering a second portion of thelabel to a surface of the label facing away from the article; andproviding full coat bonding by causing the potentially adhesiveinterface to adhere to the article subsequent to the steps of adheringthe first portion to the article and the second portion to the surfaceof the label facing away from the article.
 2. The method of claim 1wherein the potentially adhesive interface comprises a coating ofactivatable adhesive provided on the label and maintained in asubstantially non-adhesive state to allow the portion of the labelbetween the first and second portions of the label to shift on thearticle during the wrapping step.
 3. The method of claim 2 wherein thepotentially adhesive interface is a co-extruded layer of the label. 4.The method of claim 1 wherein the label is selected from the groupconsisting essentially of polyethylene, polystyrene, and polypropylene.5. The method of claim 1 wherein the step of causing the adherence ofthe potentially adhesive interface to the article is performed byheating the potentially adhesive interface of the label.
 6. The methodof claim 1 wherein the step of causing the adherence of the potentiallyadhesive interface to the article is performed by applying radiantenergy.
 7. The method of claim 1 wherein the potentially adhesiveinterface is a microencapsulated adhesive and the step of causing theinterface to adhere to the article is performed by applying a mechanicalforce to the label to cause the interface to become adhesive.
 8. Themethod of claim 1 wherein the label is heated to cause it to shrink tothe contours of the article after the step of adhering the secondportion to the article and before the step of causing the potentiallyadhesive interface to adhere to the article.
 9. The method of claim 1wherein adhering of the first portion of the label to the articleincludes applying hot melt glue to the leading and trailing ends of thelabel.
 10. The method of claim 1 wherein adhering of the first portionof the label to the article includes applying a solvent to the labelingmaterial to form an adhesive in situ.
 11. The method of claim 10 whereinthe applied solvent renders the leading edge adhesive during thewrapping step.
 12. The method of claim 1 wherein adhering of the firstportion of the label to the article includes activating limited portionsof the potentially adhesive interface to adhere the first and secondportions of the label to the article.
 13. The method of claim 1 whereinthe potentially adhesive interface is formed by printing a potentiallyadhesive material onto one entire surface of the label.
 14. The methodof claim 1 wherein the potentially adhesive interface is formed byprinting a potentially adhesive material in a pattern on the surface ofthe label.